<template>
   <div>
       <router-link
       tag="div"
       to="/"
       class="header-abs"
       v-show="showAbs"
       >
           <div class="iconfont header-abs-back">&#xe624;</div>
       </router-link>
       <div class="header-fixed" v-show="!showAbs"
       :style="opacityStyle"
       >
           <router-link to="/">
           <div class="iconfont header-fixed-back">&#xe624;</div>
       </router-link>
           景点详情
       </div>
   </div>
</template>

<script>

export default {
  name: 'DetailBanner',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.stylus'
.header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    border-radius .4rem
    text-align center
    line-height .8rem
    background rgba(0,0,0,.4)
.header-abs-back
    color #fff
    font-size .35rem
.header-fixed
    z-index 2
    position fixed
    top 0
    left 0
    right 0
    height .76rem
    line-height .86rem
    text-align center
    color #fff
    background $bgColor
    font-size .32rem
.header-fixed-back
    position absolute
    top 0
    left 0
    width .64rem
    text-align center
    font-size .4rem
    color #fff
</style>
